If your on Xbox u can also check your total playtime at the home screen somehow .. I think if you compare games

Just go to the legend thing on the left hand vertical bar and they'll be a circle with some stats a little to the right of whatever character you have. It show the games played, kills, and play time of that character. It can be switched to show PVE or PVP stats. Also, in case you didn't catch this, your total game time won't be added up across multiple characters so you'll have to add it up yourself by looking at each character.